Electric switch with transverse wiping action



y 6, 1969 G. WINTRISS 3,443,045

ELECTRIC SWITCH WITH TRANSVERSE WIPING ACTION Filed May 10, 1967 AT TORNEYS.

United States Patent O 3,443,045 ELECTRIC SWITCH WITH TRANSVERSE WIPING ACTION George Wintriss, Carversville, Pa., assignor to Industrionics Controls, Inc., New York, N.Y., a corporation of New York Filed May 10, 1967, Ser. No. 637,411

Int. Cl. H01h 1/16 US. Cl. 20083 Clanns ABSTRACT OF THE DISCLOSURE This specification discloses an electric switch with contacts that wipe over one another to keep the surface clean and without the use of a resilient arm for the movable contact. The contacts are at ditferent distances from a normal position of a flexible diaphragm that operates a movable contact structure so that this structure has to move into an oblique position, with the diaphragm distorted, in order to have the movable contact structure touch all of the contacts simultaneously. The movement into this oblique position closes the switch and causes the contacts to wipe one another; and this keeps them clean. The contacts are preferably spherical surfaces, or can be balls.

BRIEF DESCRIPTION OF THE INVENTION This is an improved electric switch having contacts that wipe one another with each operation of the switch so that contacts remain clean, avoid arcing, and give troublefree operation over extremely long periods of time.

A novel feature of the invention is that the wiping action is obtained without the use of spring arms or other resilient supporting means for the movable contact, or any of the contacts. As the switch closes, a plate that serves as the movable switch contact moves into an oblique position and its inertia causes it to slide transversely to a limited extent to produce the wiping action.

The preferred embodiment of the invention has three spherical surfaces, such as balls, held in a holder at different distances from a flexible diaphragm that divides a switch housing into a switch chamber and a pressure chamber. The diaphragm moves a movable electrical element up against the contacts, but there are means for preventing the movable element from rotating progressively in one direction with repeated cycles of the switch. In the construction illustrated, the movable element is prevented from rotating by being tightly attached to the center portion of the diaphragm.

The switch lends itself to miniaturization and operates with a minimum differential. It is especially suitable for installation where the operating signal of the switch is a pressure wave transmitted to the diaphragm through a column of gas.

Other objects, features and advantages of the invention will appear or be pointed out as the description proceeds.

BRIEF DESCRIPTION OF THE DRAWING In the drawing, forming a part hereof, in which like reference characters indicate corresponding parts in all the views:

FIGURE 1 is a vertical sectional view, taken on the line 1-1 of FIGURE 2, through a switch made in accordance with this invention;

FIGURE 2 is a sectional view taken on the line 2-2 of FIGURE 1; and

FIGURE 3 is a diagrammatic sectional view taken on the line 33 of FIGURE 2.

. with a seat 62 of a fitting 64 at the bottom Patented May 6, 1969 The switch shown in FIGURE 1 includes a housing 10 which is divided by a diaphragm 12 into a pressure chamber 14 and a switch chamber 16. The diaphragm 12 is preferably made of rubber or equivalent elastometric material.

The diaphragm 12 is clamped against a shoulder 18, in the housing, by a holder 20 which fits into the housing 10 with a press fit. The holder 20 has sockets 22 for receiving balls 24 and 25. In the preferred embodiment of the invention there are preferably three balls, a third ball 26 being shown in FIGURE 2. These balls fit into the sockets 22 with a press fit. The balls 24 and 26 are made of metal so that they are conductors of electricity. The ball 25 is made of nonelectrical-conducting material.

A movable contact structure 30', consisting of a metal plate, located on top of the diaphragm 12, is preferably attached tightly to at least the center portion of the diaphragm 12 by a hub 32 of the movable contact structure extending through the diaphragm with a rivet head 34 hearing against the underside of the diaphragm.

The diaphragm 12 is held down in a normal position, as shown in FIGURE 1, and when in this position, the diaphragm 12 and the movable contact structure 30 are substantially at right angles to a longitudinal axis 36 of the switch housing 10. The pressure for holding the diaphragm 12 and movable contact structure 30 in this normal position is supplied by a ball 38 in contact with the center of the movable contact structure 30, and by a helical spring 40 which bears against the upper surfaceof the ball 38.

The diaphragm-loading ball 38 and its spring 40 are located in a center opening 42 in a portion of the holder 20 which extends upward in the housing 10. There are threads 44 at the upper end of the opening 42; and there is a plug 46 which screws into the threads 44 and which can be moved up and down to change the loading of the spring 40. The plug 46 exerts its pressure on the spring 40 through a sealing ring 48 and a washer 50.

The pressure chamber 14 under the diaphragm 12 has a passage 52 through which fluid flows to and from the pressure chamber 14. In the illustrated construction, gas under some pressure is supplied through a fitting 54, and connecting passage 56, to the passage 52. The lower end of the passage 52 opens into a chamber 58 which is closed at its lower end by a ball 60 which contacts of the housing 10. Whenever the ball 60 is displaced upwardly, as by a cam or work piece, pressure can escape from the chamber 58 across the clearance between the ball 60 and the seat 62. This escape of pressure causes a pressure wave to pass back through the passage 52 to the chamber 14 and causes movement of the diaphragm 12 and its attached movable contact structure 30.

It will be understood that the ball 60 can be normally held away from the seat 62 so as to provide a constant and controlled escape of the gas from the chamber 58. In such a case, any change in normal operation which causes the ball 60 to contact with the seat 62 raises the pressure in the chamber 58 and produces a shock wave that travels back to the pressure chamber 14 to operate the diaphragm 12. Instead of providing for escape of gas around the ball 60 normally held out of contact with the seat 62, the ball 60 and seat 62 can be replaced with an orifice for providing a controlled escape of gas from the chamber 58 and shock waves can be produced in such a case by the passage of a work piece or other object close enough to the outlet of the orifice to affect the free discharge and to produce a shock wave back through the gas column in the passage 62. This construction for ob- 3 taining pressure variations under the diaphragm 12 is merely illustrative and forms no part of the present invention.

At the upper end of the housing 10, there is a sleeve 68 which seats against a shoulder 70 in the housing, and the sleeve 68 and housing are permanently locked together by an annular edge 72 of the housing bent into a circumferential recess 74 in the outside surface of the sleeve 68. A plug 76 fits tightly into the upper end of the sleeve 68 and this plug 76 has terminals 78 and 80 extending from its upper end and forming opposite sides of the electrical circuit of the switch.

The terminal 78 connects with a conductor 82 that contacts with the upper 'end of a spring 84' compressed between the conductor 82v and the balls 24 and 26. This spring 84 is the part of the electrical circuit which connects the ball 24 with the contact 82. The spring 84 is held in upright position by the upwardly extending portion of the holder 20. V

The terminal 80 connects with a conductor 88 at the upper end of a spring 90 which is compressed between the conductor 88 and the balls 24 and 26..The spring 90 is held out of contact with the ball 24 'by an electrical insulating washer 92. This insulating washer 92 prevents the lower end of the spring 84 from contacting with the ball 26.

The balls 24, 25 and 26 are preferably at equal radial distance from the axis 36 and they are angularly spaced around this axis. These balls are located at different distances from the normal position of the diaphragm 12 (FIGURE 1) and the plate 30. The plate 30 is preferably in constant contact with the ball 24 which comprises the fiIst fixed electrical contact of the switch. In the preferred construction, the plate 30 is made of metal which is a good conductor of electricity, such as copper, brass or aluminum, and the plate has an insert $6 of contact material, such as silver.

The ball 25 is shown in phantom in FIGURE 1 to illustrate its distance from the normal position of the movable contact structure or plate 30. As the diaphragm 12 is moved upward, the plate 30 moves about its point of tangency on the ball 24 as a center. This movement causes warping of the diaphragm 12 since the movement is a rocking movement about the point of contact with the ball 24 and not a straight-line movement in the direction of the axis 36. The diaphragm will warp in the direction which offers the least resistance since the movement of the plate 30 about its point of contact with the ball 24 is a universal movement.

Ordinarily, the plate 30 will strike the ball 25 before it strikes the ball 26 because the ball 25 is closer to the original position of the plate 30. This does not close the switch because the ball 25 is merely a support ball and is not a conductor of electricity.

Further upward movement of the diaphragm 12 causes the plate 30 to rock about an axis 98 (FIGURE 2) which extends through the points of tangency of the plate 30 and the balls 24 and 25. The support :ball 25, therefore, provides a fulcrum bearing at one side of the axis 98 so that as the plate 30 rocks about the axis 98, it moves into positionto touch the highest ball 26 which is the second fixed'switch contact. When the plate 30 touches this ball 26, the switch is closed. A contact insert 96, similarv to that shown under the ball 24 in FIGURE 1, is provided in the plate 30 under the ball 26. In rocking about the axis 98, the plate 30 moves from the solid-line position shown in FIGURE 1 to'the dotted-line position.

Since the plate 30 moves into oblique positions as it contacts successively with the balls 25 and 26, the inertia force with which it strikes the balls 25 and- 26 has a transverse component which tends to make the plate 30 slide in the plane of its top surface. Although no substantial transverse movement can take place because of the connection of the plate 30 to the diaphragm beneath it, there is sufficient elasticity in the diaphragm to permit a limited transverse movement which wipes the plate across the points of tangency on the balls and this wiping action keeps the contacts clean.

The balls 24, 25 and 26 can be ball bearings, preferably with silver plating on the balls which are part of the electrical circuit, but it is not necessary that the contacts of the switch be complete balls and the switch of this invention can also be made with spherical surfaces over only those portions of the contacts which touch the movable contact structure or plate 30. Within the broader aspects of the invention, therefore, the balls 24, 25 and 26 are merely representative of contacts which have spherical areas which touch the movable element of the switch, 'i.e., the plate 30. 4

The preferred embodiment of the invention has been illustrated and described, but changes and modifications can be made and some features can beused in different combinations without departing from the invention as defined in the claims.

What is claimed is:

1. An electric switch including a movable contact structure, a fulcrum bearing which the movable contact structure touches and on which it has rocking movement within a limited range, a relatively fixed first electrical contact with which said structure is in constant contact and on which said structure has rocking movement when moving about an axis through said fulcrum bearing and said firstvelectrical contact, and a second fixed switch contact toward and from which the movable structure moves as it rocks about said axis, the contact structure having a limited angular movement transverse of its movement toward the second switch contact and in the plane of said axis when the movable structure strikes the second switch contact whereby the movable structure wipes both of the contacts at the end of each switchclosing stroke, at least the second fixed switch contact being unloaded whereby the first part of any movement of said contact structure in the direction to open the switch moves the contact structure away from the second switch contact to open the circuit.

2. The electric switch described in claim 1 characterized by the movable contact structure being a stiff plate and at least a portion of it that extends from the fixed electrical contact to the second contact being a conductor of electricity.

3. The electric switch described in claim 2 characterized by the entire plate being made of metal and having an insert of switch contact material in its face in position to touch at least one of the contacts.

4. The electric switch described in .claim 1 characteriz ed by the movable structure being carried by a flexible diaphragm, a rigid housing having a hollow interior and in which the flexible diaphragm is a partition across said interior of the housing dividing the housing into a switch chamber and a pressure chamber having rigid side walls and with the flexible diaphragm closing one end of the pressure chamber at a shallow distance from the other end substantially less than the diameter of the flexible diaphragm, and a passage through which fluid can move to and from the pressure chamber to cause the diaphragm and the plate to move with respect to the second switch contact.

5. The electric switch described in claim characterized by the fulcrum bearing having a spherical surface and both of the electrical contacts also having spherical surfaces. v I

6. The electric switch described in claim 5 charac terized by the spherical surfaces being angularly spaced from one another about a center, and a holder by which the spherical surfaces are held, a pressure chamber,.a movable wall of the pressure chamber, the movable contact structure being connected with the movable wall and being moved thereby toward and from the holder, at least the spherical surfaces of the contacts being at different distances from a normal position of the movable wall.

7. The electric switch described in claim 6 characterized by the movable wall being a flexible diaphragm that is movable from a normal, undistorted position to a warped position that brings the movable contact structure into simultaneous contact with the spherical surfaces that are at different distances from the normal position of the diaphragm.

8. The electric switch described in claim 7 characterized by means urging the diaphragm down against the pressure in the pressure chamber, said means comprising a plunger contacting with the movable contact structure at a mid region of said structure, and resilient means pressing the plunger downward toward the diaphragm.

9. An electrical switch including a housing,.a flexible diaphragm dividing the housing into a pressure chamber and a switch chamber, a plurality of contacts above the diaphragm and in the switch chamber at angularly spaced locations from one another around a longitudinal axis of the housing, said contacts being spaced from the normal position of the diaphragm in the direction of the extent of the longitudinal axis, by different distances, at least the contact that is at the greatest distance from the diaphragm being unloaded and fixed whereby the first part of any movement of said contact structure in the direction to open the switch moves the contact structure away from the unloaded and fixed contact to .open the circuit, a plate carried by the diaphragm and movable by the diaphragm, in response to pressure changes in the pressure chamber toward and from said contacts, the diaphragm being distortable to shift the plate into an oblique position in which it touches all of said contacts simultaneously, and means in the switch chamber for preventing rotation of the plate with repeated cycles of operation of the switch.

10. The electric switch described in claim 9 characterized by the contacts being balls, a holder in which all of the balls are firmly held, diiferent conductors pressing against the different balls of the switch circuit, switch terminals to which the respective conductors are connected, the means for preventing rotation of the plate being a connection between the plate and the diaphragm.

References Cited UNITED STATES PATENTS 2,794,879 6/1957 Clason. 2,909,627 10/ 1959 Edwards. 3,153,131 10/ 1964 Gratzmuller. 3,350,530 10/1967 Fry.

FOREIGN PATENTS 956,903 9/ 1949 France.

ROBERT K. SCHAEFER, Primary Examiner. H. BURKS, Assistant Examiner.

US. Cl. X.R. 200--1 66 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,443,045

May 6, 1969 George Wintriss It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 4, line 63, after "claim" insert l Signed and sealed this 14th day of April 1970.

(SEAL) Attest:

Attesting Officer WILLIAM E. SCHUYLER, JR. 

